Prescribed daily dosage amounts for fiber are often very high, requiring the patient to administer the fiber or fiber composition several times per day. While their benefits are well known to the consuming public, the unpleasant fibrous mouthfeel and texture of products containing dietary fiber has resulted in reluctance of patients to comply with prescribed dosages.
Patient compliance with prescribed drug therapies is also a problem particularly when the drug has an unpleasant taste, after-taste or gritty mouthfeel. Drugs such as cholestryamine and potassium chloride are known to taste unpleasant. The prior art has disclosed products to mask the taste of these drugs, but the products themselves often suffer from their own unpleasant tastes. The trend, therefore, in patient use of the prior art produces containing fiber or drugs has been to deviate from the prescribed dosage or frequency of dosage, thereby diminishing the effectiveness of the therapy.
Two patents which disclose palatable drug formulations use coacervation techniques to combine cholestyramine with modified celluloses. U.S. Pat. No. 3,974,272 shows oral palatable formulations containing aqueous media and cholestyramine. A method of treating hypercholestrolemia is claimed. Chewable products containing cellulosic/gum colloids are disclosed.
U.K. Patent No. 1,446,352 concerns palatable compositions useful for the treatment of hypercholesterolemia and biliary cirrhosis. The invention provides a liquid composition containing "coacervate of cholestyramine with a cellulose hydrocolloid" derivative. By the term "coacervate" is meant the coagulation of two hydrophilic substances of opposite charge. Representative hydrocolloids are methyl and ethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose. A water-insoluble dispersing agent, e.g., a substituted carboxymethylstarch, is optional. In making the composition, 1 part by weight of hydrocolloid is combined with 4 to 10 parts of cholestyramine by dry mixing and passing through a No. 80 U.S. standard mesh screen. The resulting powder is then mixed with a liquid to form a coacervate which can be orally administered.
With respect to dietary fiber, numerous attempts to mask the fibrous mouthfeel have been tried. Various baked products, granola-type products, cereals and snack-food products have attempted to incorporate fiber in confectionery systems. These products are generally high in caloric value and relatively low in dietary fiber. The objective of the prior art has been to attempt to conceal the unpleasant taste and texture of the fiber by using various materials such as fats, polyhydric alcohols, sugar solids or starch. While the objective is achieved to some degree, these materials increase the caloric value and dilute the effective dose. High amounts of fiber, e.g., amounts greater than about 5%, typically were dry-tasting with an unpleasant fibrous mouthfeel.
Fiber products which are specifically intended for bowel normalization and related disorders include those which are slurried in water. With respect to the prior art attempts to make a fiber product which is added to water and drunk as a slurry, the fiber tended to clump together, forming slimy, unpalatable masses. These fiber clumps were comprised of hydrated hydrocolloids, e.g., pysillium. High amounts of excipients were necessary to minimize clumps. These excipients or dispersing aids were generally carbohydrate or fat materials such as sugar, dextrose and the like, which are high in caloric value.
Conventionally, fiber is incorporated into edible substances as fine powder. There are several reasons for this. Fine powdered fiber is less apt to form "fish-eye" clumps when hydrated, e.g., clumps having a dry center and wet surface. Furthermore, the purification of fiber often involves steps which reduce the particle size of fiber. Few soluble dietary fibers, with the exception of guar gum, hydrate sufficiently or uniformly unless the particle size is fine. Fine particles are, however, difficult to handle and process and product containing above 10 to 15% dietary fiber have unpalatable and fibrous textures.
It is well known that the functionality and effectiveness of fiber and certain drugs such as ion exchange resins is dependent on the active surface area. Fine particles achieve the desired therapeutic effects more effectively than coarse particles because the former have a higher surface area to weight ratio, e.g., a higher active surface. For example, in the case of ion exchange resins, e.g., cholestyramine, a greater surface area allows enhanced adsorption of bile acids, increased ion exchange, as well as other surface phenomena. In the case of fiber, increased surface area allows for increased adsorption of, and combination with, liquids, body metabolites and the like. The result is increased bulk and swelling upon adsorption which is therapeutically desirable.
While coarse substrate particles do not have sufficient effective surface area to be as effective as the finer particles, finer particles also suffer from certain handling, processing, and formulation problems. The finer particles, having a larger total surface area than coarser particles, tend to be organoleptically perceived as too dry or dusty, and in the case of certain fibers a pasty taste results. These organoleptic characteristics are undesirable. Additionally, when fine particles are added in therapeutic amounts to a delivery matrix, e.g., a confenctionery formulation, the fine particles tend to disrupt the continuous phase characteristics of the final product.
It has been discovered that these and other problems associated with coarse as well as fine substrate particles of fiber or drugs can be remedied by formation of an aggregate comprising a substantially anhydrous pre-swelled hydrocolloid and a substrate, which aggregate has a particle size of about 4 to about 70 standard U.S. mesh. Outside these ranges, some or all of the disadvantages discussed above become apparent.